Influence of instability modes on cooling performance in hypersonic boundary layer with slot injection

A combined numerical-experimental investigation is presented with focus on the effects of boundary-layer instabilities and transition wall cooling performance in a Mach 5 low-enthalpy flow over flat plate, coolant injection achieved through row slots. The numerical study has been performed direct simulation (DNS) compressible Navier-Stokes equations, supported by results from linear stability analysis (LST) for considered boundary layer. experiments have conducted High Density Tunnel (HDT) Oxford Thermofluids Institute, include several blowing ratio conditions injected air same freestream conditions. Surface heat transfer pressure measurements, film effectiveness Schlieren images are presented. links to growth imposed unstable layer modes. Results indicate that 2D 3D modes, pertaining class first instability exist laminar layer, imposition these modes at different amplitudes leads states which we refer as perturbed state transitional medium high amplitude respectively. As confirmed comparison experimental data, significantly affect performance, providing an increase flux reduction beneficial cooling.